Prevalence of Group b Streptococcus, Its Associated...
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American Journal of Health Research 2019; 7(6): 104-115
http://www.sciencepublishinggroup.com/j/ajhr
doi: 10.11648/j.ajhr.20190706.12
ISSN: 2330-8788 (Print); ISSN: 2330-8796 (Online)
Prevalence of Group b Streptococcus, Its Associated Factors and Antimicrobial Susceptibility Pattern Among Pregnant Women Attending Antenatal Care at Arbaminch Hospital, South Ethiopia
Shimelis Shiferawu1, *
, Mekidm Mekonen2, Daniel Baza
3, Temesgen Lera
4
1Department of Medical Laboratory, Wolaita Sodo University, Wolaita, Ethiopia 2School of Medical Laboratory, Jimma University, Jimma, Ethiopia 3Department of Nursing, Wolaita Sodo University, Wolaita, Ethiopia 4School of Public Health, Wolaita Sodo University, Wolaita, Ethiopia
Email address:
*Corresponding author
To cite this article: Shimelis Shiferawu, Mekidm Mekonen, Daniel Baza, Temesgen Lera. Prevalence of Group b Streptococcus, Its Associated Factors and
Antimicrobial Susceptibility Pattern Among Pregnant Women Attending Antenatal Care at Arbaminch Hospital, South Ethiopia. American
Journal of Health Research. Vol. 7, No. 6, 2019, pp. 104-115. doi: 10.11648/j.ajhr.20190706.12
Received: September 23, 2019; Accepted: October 30, 2019; Published: December 25, 2019
Abstract: Background: Group B Streptococcus colonization of the gastrointestinal and genital tracts of pregnant women usually remains asymptomatic; even if it is the critical determinant of infection in neonates and young infants. It causes early and
late onset of invasive Group B Streptococcus (GBS) disease manifesting as septicemia, meningitis and pneumonia. Now it is
recognized as an important cause of maternal and neonatal morbidity and mortality in many parts of the world including Ethiopia
where the magnitude of the problem has been little studied. Objectives: The aim of this study was to determine the prevalence of
GBS colonization, to identify associated risk factors and antimicrobial susceptibility pattern of GBS isolates among pregnant
women attending antenatal care at Arbaminch General Hospital, Arbaminch, Ethiopia. Methods: A cross sectional study was
conducted from March - July, 2016 among 281 pregnant women on their antenatal care (ANC) visit at Arbaminch General
Hospital (AGH). Consented participants’ information was collected using structured questionnaire. Recto-vaginal swab samples were collected by consecutive sampling technique and inoculated directly onto 5% sheep blood agar (SBA) for isolation of GBS.
Antimicrobial susceptibility testing was performed according to the clinical and laboratory standard institute (CLSI) guideline,
2014 by disk diffusion method. Data was coded and entered into EPidata version 3.1 and analyzed by SPSS version 21.0.
Bivariate and Multivariate logistic regression analysis were used to ascertain the association between explanatory and outcome
variable considering p-value
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105 Shimelis Shiferawu et al.: Prevalence of Group b Streptococcus, Its Associated Factors and Antimicrobial Susceptibility
Pattern Among Pregnant Women Attending Antenatal Care at Arbaminch Hospital, South Ethiopia
pregnant women and newborns [2]. The prevalence of GBS
isolation is highest in the rectum, intermediate in the vagina,
and lowest in the cervix. A combination vaginal-rectal
culture is now recommended to detect GBS in pregnant
women [1, 3].
Group B Streptococcus causes invasive disease primarily
in infants, pregnant or postpartum women, older adults, and
immunocompromised peoples with the highest incidence
among young infants [4, 5]. Many adults are
asymptomatically colonized with GBS in the genital and
gastrointestinal tracts but colonized pregnant women are at
increased risk of adverse obstetric outcomes, premature
delivery and perinatal transmission to their neonates.
Furthermore, GBS is one of the main causes of infection in
pregnant women with cystitis, chorioamnionitis,
endometritis, genitourinary tract and surgical wound
infection. Genital infection is responsible for almost one-
third of preterm deliveries, and it produce protease activity
resulting in cervical ripening [6, 7].
Group B Streptococcus is also known to infect the newborn
and hence increase the neonatal morbidity and mortality. In
pregnancy, GBS can infect the amniotic fluid, and the neonates
get colonized with it by aspiration of infected amniotic fluid or
by vertical transmission during the passage through colonized
vaginal canal and later on also from the hospital environment
or through breast feeding, leading to neonatal sepsis and
meningitis. Maternal Intrapartum GBS colonization is the most
important risk factor for developing disease in the newborn. Of
neonates that are colonized, 1–3% develops disease caused by
group B Streptococci. This infection is associated with two
distinct clinical syndromes. The first one referred to as early-
onset disease, i.e. disease appearing in their first week of life
(age 0–6 day, mainly (90%) in the first 12 hours), which is a
leading cause of invasive bacterial infection among newborns.
The other is late-onset disease that occurs at the age of 7–89
days [3, 8, 9].
In the recent decade, Group B Streptococcus (GBS) has been
one of the common causes of the early onset of sepsis among the
newborns, which leads to high rate of morbidity and mortality.
Infection by this organism may result in neonatal death due to
severe neonatal infections such as septicemia, meningitis and
pneumonia with a mortality rate of 10 - 20% [10, 11].
Despite decrease in mortality during the last decades,
Early-Onset Group B Streptococcal Disease (EOGBSD)
remains a serious neonatal condition, which may result in
severe neurological damage [12, 13]. Population-based
surveys of bacteremia have raised concerns about the
growing incidence of GBS disease in neonates [14]. Because
the colonization of this microorganism is common among
pregnant women; there is a need of having sufficient data on
the prevalence of GBS colonization, its associated risk
factors and antimicrobial susceptibility pattern of the isolates.
Therefore the present study was conducted in attempt to
expand on data regarding the problem in the study area and
contribute to the solution.
2. Methods
2.1. Study Setting and Design
The study was conducted at Arba Minch General hospital
in Arba Minch town from March to July, 2016. Arba Minch
town is found in Gamo Gofa zone, South Nations,
Nationalities’ and Peoples’ Region (SNNPR); Southern
Ethiopia. The town is 505 km to South of the Ethiopian
capital city Addis Ababa and 275 km south west of Hawassa,
the regional capital. The total area of the town is estimated
about 1095 hectares and it lies at an altitude of 1300 meters
above sea level, its average temperature is 29°C and the
average annual rainfall is 900 mm. Arba Minch hospital is a
general hospital originally built to house 50 beds but has now
expanded to 300 beds and serving a population of two
million. The Hospital provides general outpatient service,
emergency, surgical, ophthalmological, dental, psychiatric,
obstetric, fistula, Internal medical, and pediatric-neonatal as
well as leishmania in-patient services. It was recorded that a
total of 4,070 pregnant women attended the antenatal clinic
and 3,428 deliveries were attended in the year 2008 E. C
[15]. A hospital based cross sectional study design was
conducted
2.2. Sample Size and Sampling Procedure
Sample size was calculated by taking the prevalence of
colonization rate (p=20.86%) which was indicated in the
previous study in 2010 in Hawassa, South Ethiopia [16].
Expected margin of error (d) is 0.05 and confidence interval
(z) is 95%. It was calculated by using a single population
proportion formula n= (Zα/2)2 p (1−p)/d
2 and considering
10% non-response rate and the total sample calculated was
281.
Sampling Procedure
All consecutively identified pregnant women in 35-37
weeks of gestation period attending routine antenatal clinics
at Arbaminch general hospital during the study period who
fulfilled the inclusion criteria were enrolled.
2.3. Data Collection Procedure
The data on socio-demographic variables and other
relevant informations were collected by using predesigned
and pretested structured questionnaire and by reviewing
medical records. The questionnaire was adapted from other
similar studies and initially prepared in English and was
translated to Amharic and then translated back to English by
other translator to check for consistency. Informed consent
was obtained from each study participants after explaining
the purpose and procedure of the study.
2.3.1. Recto – vaginal Swab Collection
Two swab samples were collected from each woman by
using two different sterile Dacron swabs (Medical Wire and
Equipment, USA); one swab from the lower vagina (vaginal
introitus) and the other from the rectum (i.e., by inserting
swab through the anal sphincter). The swabs were collected
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by the attending midwife and nurses and transported
immediately by Amies transport media to Arba-Minch
general hospital microbiology laboratory for inoculation to 5% SBA and for further analysis, with in maximum of 4-6
hours [10, 17].
2.3.2. Culturing, Isolation and Laboratory Identification of
GBS
The swab samples were inoculated directly into 5% SBA
(Oxoid England) supplemented with 8 µg/ ml gentamicin
(CSPC Ouyi pharmaceutical co., Ltd) and was incubated
aerobically by using candle jar at 37oC for 24 hours. When
there were no colonies over 24hours, re-incubation for an
additional 24 hours was done, before discarding the plate as
negative.
Colonies were presumptively identified as GBS by colony
morphology and hemolytic activity on sheep blood agar
plates (grey mucoid colonies, surrounded by a small zone of
beta-haemolysis) and typical streptococcal morphology on
Gram stain. For confirmation, colonies from the screening
BA plates were sub cultured onto nutrient agar (Oxoid,
England) and defined as GBS on the basis of catalase
negative reaction, bacitracin resistance and CAMP test [18].
(Figure 1) Subcultures that are negative after the 1st
incubation should be incubated again overnight and re-
examined.
Figure 1. A Flow chart diagram showing Culturing, isolation and
Laboratory identification of GBS.
Figure 2. Bar graph showing antimicrobial susceptibility pattern of GBS isolates from pregnant women attending ANC in AGH from March to July, 2016
(n=24).
2.3.3. Antimicrobial Susceptibility Testing
Antimicrobial susceptibility testing was performed
according to Clinical and Laboratory Standard Institute
Guidelines (CLSI) 2014 for disk diffusion [19]. A suspension
of the test organism was prepared by removing 3-5 colonies
from a pure culture plate by emulsifying in 3 ml of sterile
physiological saline and was diluted with saline until the
turbidity of the suspension become matched with turbidity
standard equivalent to 0.5 McFarland and inoculated on
Muller-Hinton agar (MHA) with 5% sheep’s blood using a
sterile cotton swab. After the excess suspension was removed
by gentle rotation of the swab against the surface of the tube,
the swab was then used to distribute the bacteria evenly over
the entire surface of Mueller Hinton agar (Oxoid, England)
supplemented with 5% sheep blood.
The inoculated plates were left at room temperature to dry
for 3-5 minutes and a set of 6 antibiotic discs in each plate
were placed with the concentration of penicillin (P) (10µg),
ampicillin (AMP) (10µg), erythromycin (E) (15µg),
clindamycin (DA) (2µg), vancomycin (VA) (30 µg),
ceftriaxone (CRO) (30 µg), gentamicin(CN) (10 µg),
Chloramphenicol (C) (30µg), ciprofloxacin (CIP) (5µg) [20,
19] (All of the antibiotics are product of Oxoid, England and
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107 Shimelis Shiferawu et al.: Prevalence of Group b Streptococcus, Its Associated Factors and Antimicrobial Susceptibility
Pattern Among Pregnant Women Attending Antenatal Care at Arbaminch Hospital, South Ethiopia
HIMEDIA) used in the investigation. Clindamycin and
erythromycin antibiotic disks placed 12 mm from each other
in order to detect inducible resistance to clindamycin (D-zone
test) and incubated at 35-37 °C with 5% CO2 atmosphere by
candle jar for 18-24 hours. The zone of growth inhibition was
measured using rulers. The sizes of the inhibition zones was
graded according to the CLSI 2014 and interpreted as
susceptible, intermediate or resistant [19].
Data were collected using self-administered
questionnaires. The data collection tool was adapted from the
literature on maternal health surveys [22, 2, 21, 1, 4]. The
tool contained four sections which assessed socio-
demographics of HCWs, knowledge and perceptions of
HCW on pediatric emergency triage, factors associated with
quality of pediatric emergency triage as to HCWs
perspective, and observation checklists for facility visits.
Data collectors and supervisors with a nursing background
were hired and given four days training on data collection
techniques and study objectives. The triage material and
physical assessment were done via the use of a checklist on
basic triage equipment, medicines and consumables
(glucometer, IO needle, IV /rectal diazepam) as well as triage
assessment forms, triage guidelines, sick child flow charts,
the presence of a separate triage area for children and
whether or not pediatric-specific treatment algorithms were
present.
2.4. Data Quality Management
Two days training was given to the data collectors on the
purpose of study, study participants selection, on the
questionnaire, how to get informed consent, and on swab
collection and processing. Properly designed data collection
tools and protocol manuals were used. Every day the
collected data was cross checked for completeness,
consistency and on site correction action was taken. Standard
operating procedures (SOPs) were followed during sample
collection, transportation, and processing steps and protocols
were followed strictly. Stored isolates were sub-cultured
before use. Well-characterized Standard American Type
Culture Collection (ATCC) reference strain of S. aureus
(ATCC 25923), E. coli (ATCC 25922), S. agalactiae isolates
(ATCC 12386) were used to check the quality of the culture
media and antimicrobial disks, which were obtained from
SNNPR regional laboratory, Hawassa. Quality controls
including selection of satisfactory reagents, preparations,
sterility and performance of media checked according to
specific manufacturer’s instructions
The data were coded, edited and entered into Epi-data
version 3.01, cleaned and analyzed by SPSS for windows
version 20.
2.5. Data Analysis
After checking the data for completeness and
missing values, it was coded, entered into EPidata
version 3.1 and analyzed using SPSS statistical
software version 21.0. Proportions were calculated for
categorical variables and summaries were presented in terms
of counts and percentages. Explanatory variables were
individually cross tabulated with the outcome variable and
statistical significance was assessed using logistic regression
model. Odds ratio (OR) and 95% confidences interval (CI)
were calculated to determine the strength of association. P-
value less than 0.05 were considered statistically significant.
2.6. Ethical Issues
Ethical clearance was obtained from Jimma Institutional
Review Board (IRB). Written permission was obtained from
Gamo-Gofa zone health department and Arba Minch general
hospital administration. During data collection all
respondents were asked their permission and informed
consent was obtained from each study participants. In
addition, the clinical specimens collected during the study
period were used for the stated objectives only and pregnant
women who are colonized by GBS were linked to the health
professionals in the hospital in charge for possible
intervention
2.7. Operational Definitions
Colonization: the presence and multiplication of
microorganisms without tissue invasion or damage Contraceptive use is women who had ever used a
contraceptive method to delay or prevent pregnancy
Lancefield grouping: is a method of grouping catalase and
coagulase-negative bacteria based on the carbohydrate
composition of bacterial antigens found on their cell walls
Multi drug resistance: resistant to three or more
antimicrobial classes [23].
Resistant: Isolates that are resistant or intermediate
resistant to antimicrobial categories [24]
3. Result
3.1. Socio Demographic Characteristics of the Subjects
A total of 281 pregnant women in gestational age of 35-
37 weeks were participated in this study. The response rate
was 100%. Of the 281 pooled samples cultured, 24 (8.5%)
were positive for GBS.
The age of the study participants ranged from 15 to 40
years with a mean age of 25.64 and standard deviation of +
4.42 years. Majority of the study participants 115 (40.9%)
were in the age group of between 25-29 years. Most of the
study participants 265 (94.3%) were married and large
proportion of the study participants 208 (74%) were urban
residents. Most of the study participants’ ethnic group was
Gamo 189 (67.3%) and almost half of the study participants
were house wives 133 (47.3%) concerning their occupational
status. Majority of the study participants have the educational
status of Elementary school 81 (28.8%), and high Grade
(College or University) 80 (28.5%). (Table 1)
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Table 1. Socio demographic Characteristics of pregnant women.
Variables Category Frequency Percent (%)
Age (in years)
15-19 20 7.1
20-24 88 31.3
25-29 115 40.9
30-34 48 17.1
≥ 35 10 3.6
Ethnicity
Gamo 189 67.3
Gofa 16 5.7
Amhara 35 12.5
Wolaita 13 4.6
Others 28 10
Marital status
Single 14 5
Married 265 94.3
divorced / separated 2 0.7
Residence Urban 208 74
Rural 73 26
Occupation
Civil servant 64 22.8
Student 25 8.9
Farmer 8 2.8
House wife 133 47.3
Merchant(Business
women) 46 16.4
Daily Laborer 5 1.8
Educational
Status
Unable to read and
write 46 16.4
Elementary (1–8) 81 28.8
Secondary (9–12) 74 26.3
High grade (College
and University) 80 28.5
3.2. Clinical and Obstetric Data of ANC Attendants
Great majority of the study participants 200 (71.2%) were
in their multigravida. Among these 87 (31%), 50 (17.8%), 29
(10.3%), 22 (7.8%), 8 (2.8%), 3 (1.1%) and 1 (0.4%) were in
their second, third, fourth, fifth, sixth, seventh and ninth
gravida respectively. The parity of the women ranged from
zero to six. Of the 281 study participants 100 (35.6%) were
multipara. Fifteen (5.3%) and Ten (3.6%) of the study
participants have history of premature child birth and history
of PROM respectively.
History of abortion was reported from 52 (18.5%) of the
study participants. Among this 41 (78.8%), 9 (17.3%) and 2
(3.8%) mothers experienced abortion once, twice and three
times respectively in their life. From the total of 281
participants only 19 (6.8%) had a history of still birth or
neonatal loss. Regarding their gestational age of pregnancy,
most of the study participants were in their 36th
100 (35.6%)
and in their 35th
96 (34.2%) weeks of gestation during the
study period. More than half of the study participants 172
(64.9%) attended ANC four times.
From the total of 281 study participants 31 (11%) used
antibiotics in the two week time of their enrollment on our
study. Among these 9 (29%) used Amoxicillin, 6 (19.4%)
used HAART, 3 (9.7%) used Ciprofloxacin, while the rest
used combination of different antibiotics. More than half of
the study participants 163 (58%) had a history of
Contraceptive use. Of which 102 (62.6%) used Injectable, 25
(15.34%) used implant, 10 (6.1%) used oral contraceptives
(OCs), 7 (4.3%) used both injectable and implant, 3 (1.84%)
used both injectable and OCs, while Loop/IUCD, both
implant and OCs, and all contraceptives except loop were
each used by 2 (1.2%) of the contraceptive users among the
study participants. Fifty one (18.1%) of the study participants
has been diagnosed of having UTI during pregnancy.
Fourteen (5%) of the study participants were known to be
diabetic and Ten (3.6%) of participants were positive for
HIV/AIDS. (Table 2)
Table 2. Clinical and/obstetric features of pregnant women at 35-37 weeks of
gestation, who were investigated for GBS in AGH, from March to July, 2016.
Variables Category Frequency Percent (%)
History of Gravida Primigravida 81 28.8
Multigravida 200 71.2
Parity
Nullipara 91 32.4
Primipara 89 31.7
Multipara 100 35.6
Other 1
History of premat. child
birth
Yes 15 5.3
No 266 94.7
History of PROM Yes 10 3.6
No 271 96.4
History of previous
Abortion
Yes 52 18.5
No 229 81.5
still birth or Neonatal
loss hist.
Yes 19 6.8
No 262 93.2
Gestational age in
weeks
35 week 96 34.2
36 week 100 35.6
37 week 85 30.2
Number of prenatal
visit
First 5 1.9
Second 23 8.7
Third 65 24.5
Fourth 172 64.9
Other 16 5.7
Recent use of any
antibiotic R
Yes 31 11
No 248 88.3
Other 2
Contraceptive use
history
Yes 163 58
No 118 42
Dx. Of UTI during
pregnancy
Yes 51 18.1
No 230 81.9
Being Diabetic Yes 14 5
No 267 95
Recent HIV status
Positive 10 3.6
Negative 270 96.1
Other 1
3.3. Prevalence of Group B Streptococci
The overall prevalence of GBS colonization among
pregnant women’s participated in our study at 35-37 weeks
of gestation was found to be 8.5% (24/281). Two hundred
eight of the study participants were urban residents, from
which 16 (7.7%) were positive for GBS and the remaining
Seventy three were rural residents, among these 8 (11%)
were positive for GBS.
3.4. Factors Associated with GBS Colonization
3.4.1. Socio-demographic Factors
The table below (Table 3) summarized the rate of GBS
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109 Shimelis Shiferawu et al.: Prevalence of Group b Streptococcus, Its Associated Factors and Antimicrobial Susceptibility
Pattern Among Pregnant Women Attending Antenatal Care at Arbaminch Hospital, South Ethiopia
colonization by socio-demographic characteristics. The
Group B streptococcal colonization rate was higher among
pregnant mothers in the age group of 20-24 years (10.2%)
and lower in the age group of 15-19 years (5%). However,
the difference was not statistically significant (p>0.05).
Table 3. Bivariate analysis of the association between socio-demographic factors and GBS colonization among pregnant women attending ANC in AGH, from
March to July, 2016 (n=281).
variables GBS result
OR (95% C. I) P-value Positive (%) Negative (%)
Age group
15-19 1 (5) 19 (95) 1.00
20-24 9 (10.2) 79 (89.8) 0.46 (.055-3.87) 0.476
25-29 10 (8.7) 105 (91.3) 0.55 (.067-4.57) 0.582
30-34 3 (6.3) 45 (93.8) 0.79 (.077-8.08) 0.842
≥35 1 (10) 9 (90) 0.47 (.027-8.46) 0.611
Ethnicity
Gamo 18 (9.5) 171 (90.5) 1.00
Gofa 1 (6.3) 15 (93.8) 1.6 (.197-12.66) 0.667
Amhara 4 (11.4) 31 (88.6) 0.816 (.26-2.57) 0.728
Wolaita 0 (0.0) 13 (100) 0.22 (0.032-12.7) 0.96
Others 1 (3.6) 27 (96.4) 2.84 (.36-22.17) 0.319
Marital status
Single 1 (7.1) 13 (92.9) 1.00
Married 23 (8.7) 242 (91.3) 0.81 (.10-6.47) 0.842
divorced / separated 0 (0.0) 2 (100) 0.7 (0.069-14.3) 0.91
Residence
Rural 8 (11) 65 (89) 1.00
Urban 16 (7.7) 192 (92.3) 1.48 (.604-3.61) 0.393
Occupation
Merchant(Business women) 4 (8.7) 42 (91.7) 1.00
Civil servant 8 (12.5) 56 (87.5) .667 (.188-2.36) 0.530
Student 1 (4) 24 (96) 2.28 (.24-21.64) 0.471
Farmer 0 (0.0) 8 (100) 0.47 (0.09-17.1) 0.93
House wife 11 (8.3) 122 (91.7) 1.06 (.32-3.496) 0.929
Daily Laborer 0 (0.0) 5 (100) 0.49 (0.51-9.74) 0.89
Educational Status
Unable to read and write 3 (6.5) 43 (93.5) 1.82 (.47-7.08) 0.39
Elementary (1–8) 7 (8.6) 74 (91.4) 1.34 (.474-3.8) 0.581
Secondary (9–12) 5 (6.8) 69 (93.2) 1.75 (.56-5.48) 0.337
High grade completed 9 (11.3) 71 (88.8) 1.00
In this study, the highest GBS colonization rate was
detected from married pregnant mothers (8.7%). The
difference in GBS colonization rate based on marital status
was not statistically significant (p>0.05). Regarding
residence, rural residents have higher GBS colonization rate
(11%) than pregnant mothers who live in urban area (7.7%).
However, the difference was not statistically significant (P >
0.05). On the basis of occupation, in our study civil servants
have higher GBS colonization rate (12.5%), followed by
merchant/business women (8.7%). No GBS detected among
pregnant mothers who were farmers and daily laborers.
However, the difference in GBS colonization rate based on
the occupational status was not statistically significant
(p>0.05).
In the present study, even if the difference was not
statistically significant, GBS colonization rate was found
to be higher among pregnant mothers who have had
educational status of high grade (college and university)
(11.3%) and followed by elementary school (8.6%).
Generally, in this study there was no statistically
significant association observed between socio-
demographic factors and GBS colonization rate, in
bivariate analysis.
3.4.2. Obstetric/or Clinical Factors Association with GBS
Colonization
The association between GBS colonization rate and
maternal obstetric and /clinical factors is summarized in
Table 4 below. Variables candidate for multivariate logistics
regression were selected by considering p0.05). Maternal obstetric and/ clinical factors other than
them were also not significantly associated statistically with
GBS colonization rate.
Regarding gravidity, the GBS colonization rate was almost
the same in both primigravida (8.6%) and multigravida
(8.5%) mothers. Based on parity, nullipara had higher GBS
colonization rate (11%) than multipara (9%) and primipara
(5.6%). However, the difference was not statistically
significant (p>0.05). This study indicated that pregnant
mothers with previous history of PROM has slightly higher
rate of GBS colonization (10%) than pregnant mothers who
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American Journal of Health Research 2019; 7(6): 104-115 110
had no history of PROM (5.9%); even if the difference was
not statistically significant (P > 0.05).
In our study, although it was not significantly associated
(p>0.05), maternal GBS colonization was about four fold
higher in mothers with history of abortion than those without
history of abortion (15.4% vs 3.9%). Pregnant women who
had previous history of still birth or neonatal loss has
somewhat higher rate of GBS colonization (10.5%) than
those with no history of still birth or neonatal loss (5.7%).
However, this difference was not statistically significant (P >
0.05). Group B streptococcal colonization rate was higher in
those pregnant mothers who visited ANC once (40%) than
those visited four times (11.6%), twice (4.3%) and three
times (0.0%) during pregnancy in this study. But, the
difference was not statistically significant (P > 0.05).
On the basis of history of recent use of any antibiotic
treatment, the GBS colonization rate was higher among
pregnant mothers who had no history of antibiotic treatment
(8.9%) than those who had history of antibiotic treatment
(6.5%); even if the difference was not statistically
significant(p>0.05). In this study pregnant mothers who had
no history of any contraceptive use were colonized by GBS
largely (11%) than those mothers who had a history of
contraceptive use (6.7%). However, the difference was not
statistically significant (p>0.05).
It was showed that in the current study, pregnant women
who had not been diagnosed of having UTI during pregnancy
had slightly higher rate of GBS colonization (8.7%) than
those who had been diagnosed of having UTI during
pregnancy (7.8%). However, this difference was not
statistically significant (P > 0.05). Although, there was no
statistically significant association (p>0.05), the GBS
colonization rate was higher among diabetic pregnant
mothers (14.3%) in relation to non-diabetic pregnant mothers
(8.2%). Pregnant women’s who were positive for HIV/AIDS
were a little highly colonized with GBS (10%) than those
mothers who were negative for HIV/AIDS infection (8.5%).
But the difference was not statistically significant (p>0.05)
(see Table 4).
Table 4. Association between clinical/obstetric factors and GBS colonization among pregnant women attending ANC in AGH, from March to July, 2016
(n=281).
Variable n GBS result
COR (95% C. I) p-valuex AOR (95% C. I) p-valuey Pos. (%) Neg. (%)
History of Gravida
Primigravida 81 7 (8.6) 74 (91.4) 0.98 (.39-2.466) 0.97
Multigravida 200 17 (8.5) 183 (91.5) 1.00
Parity
Nullipara 91 10 (11) 81 (89) 1.00 1.00
Primipara 89 5 (5.6) 84 (94.4) 2.07 (.68-6.33) 0.200 2.99 (.408-21.95) 0.281
Multipara 100 9 (9) 91 (91) 1.25 (.483-3.22) 0.647 1.85 (.317-10.79) 0.494
Others 1 - - - -
History of prematu. child birth
Yes 15 1 (6.7) 14 (93.3) 1.00
No 266 16 (6) 250 (94) .773 (.095-6.28) 0.81
History of PROM
Yes 10 1 (10.0) 9 (90) 1.00
No 271 16 (5.9) 174 (94.1) 1.11 (13- 9.46) 0.924
History of Abortion
Yes 52 8 (15.4) 44 (84.6) 1.00 1.00
No 229 9 (3.9) 220 (96.1) 2.82 (1.02-7.8) 0.045 1.9 (571-6.33) 0.295
History of still birth/Neonatal loss
Yes 19 2 (10.5) 17 (89.5) 1.00
No 262 15 (5.7) 247 (94.3) 1.41 (.29-6.8) 0.671
Gestational age
35 week 96 10 (10.4) 86 (89.6) 1.00
36 week 100 9 (9) 91 (91) 1.18 (.46 -3.03) 0.74
37 week 85 5 (5.9) 80 (94.1) 1.86 (.61-5.68) 0.276
No. of ANC visit
First 5 2 (40) 3 (60) 1.79 (.03-1.254) 0.085 0.267 (.036-1.98) 0.197
Second 23 1 (4.3) 22 (95.7) 2.89 (37-22.66) 0.311 2.65 (3-23.4) 0.381
Third 65 0 (0.0) 65 (100) 0.2 (.15-16.84) 0.89 0.11 (.23- 9.65) 0.93
Fourth 172 20 (11.6 152 (88.4) 1.00 1.00
Other 16 - - -
Recent antibiotic Rx
Yes 31 2 (6.5) 29 (93.5) 1.41 (.315-6.31) 0.652
No 248 22 (8.9) 226 (91.1) 1.00
Others 2 - - - -
Contraceptive use history
Yes 163 11 (6.7) 152 (93.3) 1.00 1.00
No 118 13 (11) 105 (89) 0.585 (25-1.36) 0.211 0.438 (13-1.48) 0.184
UTI during pregnancy
Yes 51 4 (7.8) 47 (92.2) 1.00
-
111 Shimelis Shiferawu et al.: Prevalence of Group b Streptococcus, Its Associated Factors and Antimicrobial Susceptibility
Pattern Among Pregnant Women Attending Antenatal Care at Arbaminch Hospital, South Ethiopia
Variable n GBS result
COR (95% C. I) p-valuex AOR (95% C. I) p-valuey Pos. (%) Neg. (%)
No 230 20 (8.7) 210 (91.3) 905 (295-2.78) 0.861
Being Diabetic
Yes 14 2 (14.3) 12 (85.7) 1.00
No 267 22 (8.2) 245 (91.8) 1.856 (39-8.83) 0.437
Recent HIV status
Positive 10 (10.0) 9 (90) 1.00
Negative 270 23 (8.5) 247 (91.5) 1.2 (145-9.84) 0.87
Other 1 - - - -
3.5. Antimicrobial Susceptibility Testing
All GBS isolates were susceptible to penicillin, Ampicillin
and Vancomycin. Utmost isolates were susceptible for
Gentamycin 23 (95.8%) and chloramphenicol 22 (91.7%).
Resistance to Ciprofloxacin, Ceftriaxone, Clindamycin,
Erythromycin and Gentamycin was found to be 37.5%,
29.2%, 29.2%, 20.8% and 4.2% respectively. Of the seven
isolates found to be resistant to clindamycin 2 (28.6%) were
found by inducible clindamycin resistance test (D-zone test)
and the remaining 5 (71.4%) were found directly from disk
diffusion test. 29.2% and 8.3% intermediate sensitivity to
Ceftriaxone and Erythromycin respectively was also found in
our study. Two of the GBS isolates (2/24) showed multidrug
resistance against Ceftriaxone, Erythromycin, Clindamycin
and ciprofloxacin. (Table 5)
Table 5. Antimicrobial susceptibility pattern of GBS isolates from pregnant
women attending ANC in AGH from March to July, 2016 (n=24).
Antimicrobial Disc potency (µg) Sensitive N (%) Resistant N (%)
Penicillin G 10 24 (100) 0
Ampicillin 10 24 (100) 0
Chloramphenicol 30 22 (91.7) 2
Ceftriaxone 30 17 (70.8) 7 (29.2)
Vancomycin 30 24 (100) 0
Erythromycin 15 19 (79.2) 5
Clindamycin 2 17 (70.8) 7 (29.2)
Gentamycin 10 23 (95.8) 1
Ciprofloxacillin 5 15 (62.5) 9 (37.5)
4. Discussion
The current investigation indicates an overall prevalence
of 8.5% S. agalactiae. The finding is similar to the initial
study done in Ethiopia which was carried out in Gonder with
the colonization rate of 9%, studies at two hospitals in Addis
Ababa with the colonization rate of 7.2% and Adigrat
(11.3%) in 2012, [25-27]. But, it is lower than the prevalence
reports from studies in different regions of Ethiopia; like
Mekelle (13.7%), Hawassa (20.86%) and Jimma with overall
carriage rate of 19% [16, 20, 28]. This variation between the
regions could possibly be due to differences in method used,
sample size, population variation and geographical
difference. The result of this study is also consistent with
reports from other developing African countries such as
Yaoundé, Cameroon in (7.7%), and North eastern Nigeria
(9.8%) [29, 30]. The finding is higher than the prevalence
report from some African countries, such as Maputo,
Mozambique (1.8%) [31] and lower than the prevalence rates
described for some African countries, such as Egypt
(17.89%), Democratic Republic of Congo (20%), Zimbabwe
(21%) and Tanzania (23%) [32-35]. The difference in
frequency could be due to variation in sample size, method
used, culture media used and geographic differences. For
example in our study we haven’t used the primary isolation
media, Todd-Hewitt broth (THB) media, which is selective
for GBS.
In the current study no risk factors is associated with GBS
colonization. This finding similar with studies conducted in
Brazil; Hedayat Hospital of Tehran; Dares Salam-Tanzania; a
pilot study in Ghana; in Hawassa, in Mekelle and in Jimma
[16, 33, 36-39, 20, 28]. This could be due to small sample
size in the current study.
Contrarily, in a study conducted in Daejeon- Korea, GBS
colonization was significantly associated with hospital type,
age group, education, frequency of pregnancy, gravidity,
history of spontaneous abortion and PROM [40]. This
difference could probably be due to difference in sample size,
methodology and. geographic variation.
Even if it is not statistically significant, the GBS
colonization rate in our study was higher among rural
resident than urban residents (11% vs 7.7%). This could be
due to personal hygiene and environmental sanitation
difference between rural and urban population. However, two
studies conducted in Zimbabwe showed significant
association of GBS colonization among rural residents
compared to urban residents [31, 41]. The difference may be
related with awareness and behavioral variation. In the
current study, GBS colonization didn’t vary significantly
with occupational status in which, civil servants have higher
GBS colonization rate (12.5%), followed by
merchant/business women (8.7%); which is parallel with
study conducted in Hong Kong that showed high GBS
colonization rate among pregnant women who work outside
home [42]. This may partially be explained by their exposure
difference. No GBS detected among pregnant mothers who
were farmers and daily laborers in our study; which could be
due to very small number of participants with these
occupations.
Group B Streptococcus colonization in our study is almost
similar in primigravida (8.6%) and multigravida (8.5%). This
finding is somewhat different from studies reported from
Nigeria, Ethiopia and Ghana, in which there is substantial
variation in GBS colonization based on gravidity; even if it is
not statistically significant [16, 43, 39]. However, in other
studies conducted at Jawaharlal Institute of Postgraduate
-
American Journal of Health Research 2019; 7(6): 104-115 112
Medical Education and Research (JIPMER), South India
(p=0.05) and Mount Hope Maternity hospital and the San
Fernando General Hospital of Trinidad (P
-
113 Shimelis Shiferawu et al.: Prevalence of Group b Streptococcus, Its Associated Factors and Antimicrobial Susceptibility
Pattern Among Pregnant Women Attending Antenatal Care at Arbaminch Hospital, South Ethiopia
Serotyping of GBS ought to be performed in future researches,
because it is an effective epidemiological tool for studying
GBS. The current study was conducted in small sample size;
therefore further comprehensive epidemiological survey to
establish the GBS colonization rate among pregnant mothers at
different gestational ages and the effects of it on both maternal
and neonatal outcome of pregnancy need to be conducted to
introduce national guideline.
Competing Interests
The authors have declared that no competing interests
exist.
Acknowledgements
We would like to forward our gratitude to Jimma
University, School of Allied Health Sciences. We thank also
Gamo Gofa Zone administrators, the supervisors,
respondents and Data Collectors.
Authors’ Contribution
SS, MM, DB, ZS and TL
All authors equally contributed to this research work *These authors read and approved the final manuscript
Abbreviation and Acronyms
AGH. Arbaminch General Hospital, ANC Antenatal care,
ATCC. American Type culture collection, BA Blood Agar,
CAMP Christie, Atkins, and Munich-Prevention, CDC .
Center for Disease Control and prevention, I Confidence
Interval, CLSI Clinical and Laboratory Standard Institute,
EOGBSD Early-Onset group B streptococcal Disease, GBS
Group B streptococcus/Streptococci, HIV Human
Immunodeficiency Virus, IAP Intrapartum Antibiotics
Prophylaxis, IRB Institutional review board, LOGBSD. Late-
Onset Group B Streptococcal Disease, MHA Late- Onset
Group B Streptococcal Disease, OR Odds ratio, PMROM
Premature Rupture of Membranes, SBA Sheep Blood Agar,
SNNPR Southern Nations, Nationalities and Peoples Region,
SOS Standard Operating Procedures, SPSS Statistical
Package for Social Sciences, THB Todd Hewitt Broth, UTI
Urinary Tract Infection.
Availability of Data & Materials
The data for this research is available, so we can contact
you when you need our data for the future process.
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